1. Field of the Invention
The present invention relates generally to solar cells, and more particularly but not exclusively to solar cell installations.
2. Description of the Background Art
Solar cells are well known devices for converting solar radiation to electrical energy. They may be fabricated on a semiconductor wafer using semiconductor processing technology. Generally speaking, a solar cell may be fabricated by forming P-type and N-type diffusion regions in a silicon substrate. Solar radiation impinging on the solar cell creates electrons and holes that migrate to the diffusion regions, thereby creating voltage differentials between the diffusion regions. In a back-junction solar cell, both the diffusion regions and the metal grids coupled to them are on the back side of the solar cell. The metal grids allow an external electrical circuit to be coupled to and be powered by the solar cell.
A solar cell installation, such as that shown in FIG. 1, typically includes a plurality of solar cells that are strung together to generate power delivered to a load, such as an inverter. In FIG. 1, the installation includes a solar cell module 100 that comprises a plurality of solar cell strings 104, each with a set of solar cells 102 and a diode D1. The installation may include more than one solar cell module. A maximum power point tracking and regulator module 103 optimizes the power delivered to the load on a global basis for the entire installation regardless of the number of solar cell modules employed.
Each set of solar cells 102 may comprise a plurality of solar cells arranged in serial fashion. Each diode D1 allows for removal of a string 104 from the installation in the event the string 104 is faulty or drags down the overall power generation capability of the installation. During normal operation, a substring 104 generates power such that it has the polarity shown in FIG. 1. In that case, the diode D1 is reversed bias and has no electrical influence on the installation. In the event of a failure, a string 104 changes polarity such that its corresponding diode D1 is forward biased, thereby shunting off that string 104 from the installation.
Although the installation of FIG. 1 and similar installations provide much needed renewable energy source, techniques for improving their power generation capability would make them more economically viable for widespread use.